MEXICO CITY (Reuters) – Mexican President Andres Manuel Lopez Obrador said on Monday his country would, for “humanitarian” reasons, sell gasoline to Venezuela if asked to do so, despite a raft of U.S. sanctions imposed on the South American country and its state-run oil company, PDVSA.

Lopez Obrador added he had not received such a request from the Venezuelan government.

The U.S. administration is seeking to choke Venezuelan oil exports to starve the government of socialist President Nicolas Maduro of its main source of revenue. Tightening sanctions have cut Venezuelan exports sharply, but Maduro has held on.

As Venezuela suffers a severe gasoline shortage, Iran sent a flotilla of five cargoes to the country from late May through early June, despite Washington’s criticism of the trade between the two nations, which are under sanctions.

Nevertheless, Lopez Obrador said he would be willing to send gasoline to Venezuela under the right circumstances.

“Mexico is an independent, sovereign country,” he said during his regular morning news conference. “We make our own decisions and do not mess with the policies of other countries.”

The United States, which did not hinder Iran’s tanker cargoes but could punish firms related to the trade, is considering imposing sanctions on dozens of additional foreign oil tankers that have transported Venezuelan oil, a U.S. official told Reuters earlier this month.

Despite pressure from the United States, Iran plans to maintain its fuel shipments to Venezuela, sources said. The country could send two to three gasoline cargoes a month to its Latin American ally, the sources said.

Long lines of drivers waiting to fill their tanks with imported gasoline in Venezuela have recently eased at stations where fuel is sold in foreign currency, following a price hike earlier this month. But waits persist at stations offering subsidized fuel in several regions.